coreutils/dd.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * Mini dd implementation for busybox
   4  *
   5  * Copyright (C) 2000,2001  Matt Kraai
   6  *
   7  * Licensed under GPLv2 or later, see file LICENSE in this source tree.
   8  */
   9 //config:config DD
  10 //config:       bool "dd (7.1 kb)"
  11 //config:       default y
  12 //config:       help
  13 //config:       dd copies a file (from standard input to standard output,
  14 //config:       by default) using specific input and output blocksizes,
  15 //config:       while optionally performing conversions on it.
  16 //config:
  17 //config:config FEATURE_DD_SIGNAL_HANDLING
  18 //config:       bool "Enable signal handling for status reporting"
  19 //config:       default y
  20 //config:       depends on DD
  21 //config:       help
  22 //config:       Sending a SIGUSR1 signal to a running 'dd' process makes it
  23 //config:       print to standard error the number of records read and written
  24 //config:       so far, then to resume copying.
  25 //config:
  26 //config:       $ dd if=/dev/zero of=/dev/null &
  27 //config:       $ pid=$!; kill -USR1 $pid; sleep 1; kill $pid
  28 //config:       10899206+0 records in
  29 //config:       10899206+0 records out
  30 //config:
  31 //config:config FEATURE_DD_THIRD_STATUS_LINE
  32 //config:       bool "Enable the third status line upon signal"
  33 //config:       default y
  34 //config:       depends on DD && FEATURE_DD_SIGNAL_HANDLING
  35 //config:       help
  36 //config:       Displays a coreutils-like third status line with transferred bytes,
  37 //config:       elapsed time and speed.
  38 //config:
  39 //config:config FEATURE_DD_IBS_OBS
  40 //config:       bool "Enable ibs, obs, iflag and conv options"
  41 //config:       default y
  42 //config:       depends on DD
  43 //config:       help
  44 //config:       Enable support for writing a certain number of bytes in and out,
  45 //config:       at a time, and performing conversions on the data stream.
  46 //config:
  47 //config:config FEATURE_DD_STATUS
  48 //config:       bool "Enable status display options"
  49 //config:       default y
  50 //config:       depends on DD
  51 //config:       help
  52 //config:       Enable support for status=noxfer/none option.
  53
  54 //applet:IF_DD(APPLET_NOEXEC(dd, dd, BB_DIR_BIN, BB_SUID_DROP, dd))
  55
  56 //kbuild:lib-$(CONFIG_DD) += dd.o
  57
  58 //usage:#define dd_trivial_usage
  59 //usage:       "[if=FILE] [of=FILE] " IF_FEATURE_DD_IBS_OBS("[ibs=N] [obs=N] ") "[bs=N] [count=N] [skip=N]\n"
  60 //usage:       "        [seek=N]" IF_FEATURE_DD_IBS_OBS(" [conv=notrunc|noerror|sync|fsync] [iflag=skip_bytes|fullblock]")
  61 //usage:#define dd_full_usage "\n\n"
  62 //usage:       "Copy a file with converting and formatting\n"
  63 //usage:     "\n        if=FILE         Read from FILE instead of stdin"
  64 //usage:     "\n        of=FILE         Write to FILE instead of stdout"
  65 //usage:     "\n        bs=N            Read and write N bytes at a time"
  66 //usage:        IF_FEATURE_DD_IBS_OBS(
  67 //usage:     "\n        ibs=N           Read N bytes at a time"
  68 //usage:        )
  69 //usage:        IF_FEATURE_DD_IBS_OBS(
  70 //usage:     "\n        obs=N           Write N bytes at a time"
  71 //usage:        )
  72 //usage:     "\n        count=N         Copy only N input blocks"
  73 //usage:     "\n        skip=N          Skip N input blocks"
  74 //usage:     "\n        seek=N          Skip N output blocks"
  75 //usage:        IF_FEATURE_DD_IBS_OBS(
  76 //usage:     "\n        conv=notrunc    Don't truncate output file"
  77 //usage:     "\n        conv=noerror    Continue after read errors"
  78 //usage:     "\n        conv=sync       Pad blocks with zeros"
  79 //usage:     "\n        conv=fsync      Physically write data out before finishing"
  80 //usage:     "\n        conv=swab       Swap every pair of bytes"
  81 //usage:     "\n        iflag=skip_bytes        skip=N is in bytes"
  82 //usage:     "\n        iflag=fullblock Read full blocks"
  83 //usage:        )
  84 //usage:        IF_FEATURE_DD_STATUS(
  85 //usage:     "\n        status=noxfer   Suppress rate output"
  86 //usage:     "\n        status=none     Suppress all output"
  87 //usage:        )
  88 //usage:     "\n"
  89 //usage:     "\nN may be suffixed by c (1), w (2), b (512), kB (1000), k (1024), MB, M, GB, G"
  90 //usage:
  91 //usage:#define dd_example_usage
  92 //usage:       "$ dd if=/dev/zero of=/dev/ram1 bs=1M count=4\n"
  93 //usage:       "4+0 records in\n"
  94 //usage:       "4+0 records out\n"
  95
  96 #include "libbb.h"
  97 #include "common_bufsiz.h"
  98
  99 /* This is a NOEXEC applet. Be very careful! */
 100
 101
 102 enum {
 103         ifd = STDIN_FILENO,
 104         ofd = STDOUT_FILENO,
 105 };
 106
 107 struct globals {
 108         off_t out_full, out_part, in_full, in_part;
 109 #if ENABLE_FEATURE_DD_THIRD_STATUS_LINE
 110         unsigned long long total_bytes;
 111         unsigned long long begin_time_us;
 112 #endif
 113         int flags;
 114 } FIX_ALIASING;
 115 #define G (*(struct globals*)bb_common_bufsiz1)
 116 #define INIT_G() do { \
 117         setup_common_bufsiz(); \
 118         /* we have to zero it out because of NOEXEC */ \
 119         memset(&G, 0, sizeof(G)); \
 120 } while (0)
 121
 122 enum {
 123         /* Must be in the same order as OP_conv_XXX! */
 124         /* (see "flags |= (1 << what)" below) */
 125         FLAG_NOTRUNC = (1 << 0) * ENABLE_FEATURE_DD_IBS_OBS,
 126         FLAG_SYNC    = (1 << 1) * ENABLE_FEATURE_DD_IBS_OBS,
 127         FLAG_NOERROR = (1 << 2) * ENABLE_FEATURE_DD_IBS_OBS,
 128         FLAG_FSYNC   = (1 << 3) * ENABLE_FEATURE_DD_IBS_OBS,
 129         FLAG_SWAB    = (1 << 4) * ENABLE_FEATURE_DD_IBS_OBS,
 130         /* end of conv flags */
 131         /* start of input flags */
 132         FLAG_IFLAG_SHIFT = 5,
 133         FLAG_SKIP_BYTES = (1 << 5) * ENABLE_FEATURE_DD_IBS_OBS,
 134         FLAG_FULLBLOCK = (1 << 6) * ENABLE_FEATURE_DD_IBS_OBS,
 135         /* end of input flags */
 136         FLAG_TWOBUFS = (1 << 7) * ENABLE_FEATURE_DD_IBS_OBS,
 137         FLAG_COUNT   = 1 << 8,
 138         FLAG_STATUS_NONE = 1 << 9,
 139         FLAG_STATUS_NOXFER = 1 << 10,
 140 };
 141
 142 static void dd_output_status(int UNUSED_PARAM cur_signal)
 143 {
 144 #if ENABLE_FEATURE_DD_THIRD_STATUS_LINE
 145         double seconds;
 146         unsigned long long bytes_sec;
 147         unsigned long long now_us = monotonic_us(); /* before fprintf */
 148 #endif
 149
 150         /* Deliberately using %u, not %d */
 151         fprintf(stderr, "%"OFF_FMT"u+%"OFF_FMT"u records in\n"
 152                         "%"OFF_FMT"u+%"OFF_FMT"u records out\n",
 153                         G.in_full, G.in_part,
 154                         G.out_full, G.out_part);
 155
 156 #if ENABLE_FEATURE_DD_THIRD_STATUS_LINE
 157 # if ENABLE_FEATURE_DD_STATUS
 158         if (G.flags & FLAG_STATUS_NOXFER) /* status=noxfer active? */
 159                 return;
 160         //TODO: should status=none make dd stop reacting to USR1 entirely?
 161         //So far we react to it (we print the stats),
 162         //status=none only suppresses final, non-USR1 generated status message.
 163 # endif
 164         fprintf(stderr, "%llu bytes (%sB) copied, ",
 165                         G.total_bytes,
 166                         /* show fractional digit, use suffixes */
 167                         make_human_readable_str(G.total_bytes, 1, 0)
 168         );
 169         /* Corner cases:
 170          * ./busybox dd </dev/null >/dev/null
 171          * ./busybox dd bs=1M count=2000 </dev/zero >/dev/null
 172          * (echo DONE) | ./busybox dd >/dev/null
 173          * (sleep 1; echo DONE) | ./busybox dd >/dev/null
 174          */
 175         seconds = (now_us - G.begin_time_us) / 1000000.0;
 176         bytes_sec = G.total_bytes / seconds;
 177         fprintf(stderr, "%f seconds, %sB/s\n",
 178                         seconds,
 179                         /* show fractional digit, use suffixes */
 180                         make_human_readable_str(bytes_sec, 1, 0)
 181         );
 182 #endif
 183 }
 184
 185 static ssize_t full_write_or_warn(const void *buf, size_t len,
 186         const char *const filename)
 187 {
 188         ssize_t n = full_write(ofd, buf, len);
 189         if (n < 0)
 190                 bb_perror_msg("writing '%s'", filename);
 191         return n;
 192 }
 193
 194 static bool write_and_stats(const void *buf, size_t len, size_t obs,
 195         const char *filename)
 196 {
 197         ssize_t n = full_write_or_warn(buf, len, filename);
 198         if (n < 0)
 199                 return 1;
 200 #if ENABLE_FEATURE_DD_THIRD_STATUS_LINE
 201         G.total_bytes += n;
 202 #endif
 203         if ((size_t)n == obs) {
 204                 G.out_full++;
 205                 return 0;
 206         }
 207         if ((size_t)n == len) {
 208                 G.out_part++;
 209                 return 0;
 210         }
 211         return 1;
 212 }
 213
 214 #if ENABLE_LFS
 215 # define XATOU_SFX xatoull_sfx
 216 #else
 217 # define XATOU_SFX xatoul_sfx
 218 #endif
 219
 220 #if ENABLE_FEATURE_DD_IBS_OBS
 221 static int parse_comma_flags(char *val, const char *words, const char *error_in)
 222 {
 223         int flags = 0;
 224         while (1) {
 225                 int n;
 226                 char *arg;
 227                 /* find ',', replace them with NUL so we can use val for
 228                  * index_in_strings() without copying.
 229                  * We rely on val being non-null, else strchr would fault.
 230                  */
 231                 arg = strchr(val, ',');
 232                 if (arg)
 233                         *arg = '\0';
 234                 n = index_in_strings(words, val);
 235                 if (n < 0)
 236                         bb_error_msg_and_die(bb_msg_invalid_arg_to, val, error_in);
 237                 flags |= (1 << n);
 238                 if (!arg) /* no ',' left, so this was the last specifier */
 239                         break;
 240                 *arg = ','; /* to preserve ps listing */
 241                 val = arg + 1; /* skip this keyword and ',' */
 242         }
 243         return flags;
 244 }
 245 #endif
 246
 247 int dd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 248 int dd_main(int argc UNUSED_PARAM, char **argv)
 249 {
 250         static const char keywords[] ALIGN1 =
 251                 "bs\0""count\0""seek\0""skip\0""if\0""of\0"IF_FEATURE_DD_STATUS("status\0")
 252 #if ENABLE_FEATURE_DD_IBS_OBS
 253                 "ibs\0""obs\0""conv\0""iflag\0"
 254 #endif
 255                 ;
 256 #if ENABLE_FEATURE_DD_IBS_OBS
 257         static const char conv_words[] ALIGN1 =
 258                 "notrunc\0""sync\0""noerror\0""fsync\0""swab\0";
 259         static const char iflag_words[] ALIGN1 =
 260                 "skip_bytes\0""fullblock\0";
 261 #endif
 262 #if ENABLE_FEATURE_DD_STATUS
 263         static const char status_words[] ALIGN1 =
 264                 "none\0""noxfer\0";
 265 #endif
 266         enum {
 267                 OP_bs = 0,
 268                 OP_count,
 269                 OP_seek,
 270                 OP_skip,
 271                 OP_if,
 272                 OP_of,
 273                 IF_FEATURE_DD_STATUS(OP_status,)
 274 #if ENABLE_FEATURE_DD_IBS_OBS
 275                 OP_ibs,
 276                 OP_obs,
 277                 OP_conv,
 278                 OP_iflag,
 279                 /* Must be in the same order as FLAG_XXX! */
 280                 OP_conv_notrunc = 0,
 281                 OP_conv_sync,
 282                 OP_conv_noerror,
 283                 OP_conv_fsync,
 284                 OP_conv_swab,
 285         /* Unimplemented conv=XXX: */
 286         //nocreat       do not create the output file
 287         //excl          fail if the output file already exists
 288         //fdatasync     physically write output file data before finishing
 289         //lcase         change upper case to lower case
 290         //ucase         change lower case to upper case
 291         //block         pad newline-terminated records with spaces to cbs-size
 292         //unblock       replace trailing spaces in cbs-size records with newline
 293         //ascii         from EBCDIC to ASCII
 294         //ebcdic        from ASCII to EBCDIC
 295         //ibm           from ASCII to alternate EBCDIC
 296         /* Partially implemented: */
 297         //swab          swap every pair of input bytes: will abort on non-even reads
 298                 OP_iflag_skip_bytes,
 299                 OP_iflag_fullblock,
 300 #endif
 301         };
 302         smallint exitcode = EXIT_FAILURE;
 303         int i;
 304         size_t ibs = 512;
 305         char *ibuf;
 306 #if ENABLE_FEATURE_DD_IBS_OBS
 307         size_t obs = 512;
 308         char *obuf;
 309 #else
 310 # define obs  ibs
 311 # define obuf ibuf
 312 #endif
 313         /* These are all zeroed at once! */
 314         struct {
 315                 size_t oc;
 316                 ssize_t prev_read_size; /* for detecting swab failure */
 317                 off_t count;
 318                 off_t seek, skip;
 319                 const char *infile, *outfile;
 320         } Z;
 321 #define oc      (Z.oc     )
 322 #define prev_read_size (Z.prev_read_size)
 323 #define count   (Z.count  )
 324 #define seek    (Z.seek   )
 325 #define skip    (Z.skip   )
 326 #define infile  (Z.infile )
 327 #define outfile (Z.outfile)
 328
 329         memset(&Z, 0, sizeof(Z));
 330         INIT_G();
 331         //fflush_all(); - is this needed because of NOEXEC?
 332
 333         for (i = 1; argv[i]; i++) {
 334                 int what;
 335                 char *val;
 336                 char *arg = argv[i];
 337
 338 #if ENABLE_DESKTOP
 339                 /* "dd --". NB: coreutils 6.9 will complain if they see
 340                  * more than one of them. We wouldn't. */
 341                 if (arg[0] == '-' && arg[1] == '-' && arg[2] == '\0')
 342                         continue;
 343 #endif
 344                 val = strchr(arg, '=');
 345                 if (val == NULL)
 346                         bb_show_usage();
 347                 *val = '\0';
 348                 what = index_in_strings(keywords, arg);
 349                 if (what < 0)
 350                         bb_show_usage();
 351                 /* *val = '='; - to preserve ps listing? */
 352                 val++;
 353 #if ENABLE_FEATURE_DD_IBS_OBS
 354                 if (what == OP_ibs) {
 355                         /* Must fit into positive ssize_t */
 356                         ibs = xatoul_range_sfx(val, 1, ((size_t)-1L)/2, cwbkMG_suffixes);
 357                         /*continue;*/
 358                 }
 359                 if (what == OP_obs) {
 360                         obs = xatoul_range_sfx(val, 1, ((size_t)-1L)/2, cwbkMG_suffixes);
 361                         /*continue;*/
 362                 }
 363                 if (what == OP_conv) {
 364                         G.flags |= parse_comma_flags(val, conv_words, "conv");
 365                         /*continue;*/
 366                 }
 367                 if (what == OP_iflag) {
 368                         G.flags |= parse_comma_flags(val, iflag_words, "iflag") << FLAG_IFLAG_SHIFT;
 369                         /*continue;*/
 370                 }
 371 #endif
 372                 if (what == OP_bs) {
 373                         ibs = xatoul_range_sfx(val, 1, ((size_t)-1L)/2, cwbkMG_suffixes);
 374                         obs = ibs;
 375                         /*continue;*/
 376                 }
 377                 /* These can be large: */
 378                 if (what == OP_count) {
 379                         G.flags |= FLAG_COUNT;
 380                         count = XATOU_SFX(val, cwbkMG_suffixes);
 381                         /*continue;*/
 382                 }
 383                 if (what == OP_seek) {
 384                         seek = XATOU_SFX(val, cwbkMG_suffixes);
 385                         /*continue;*/
 386                 }
 387                 if (what == OP_skip) {
 388                         skip = XATOU_SFX(val, cwbkMG_suffixes);
 389                         /*continue;*/
 390                 }
 391                 if (what == OP_if) {
 392                         infile = val;
 393                         /*continue;*/
 394                 }
 395                 if (what == OP_of) {
 396                         outfile = val;
 397                         /*continue;*/
 398                 }
 399 #if ENABLE_FEATURE_DD_STATUS
 400                 if (what == OP_status) {
 401                         int n;
 402                         n = index_in_strings(status_words, val);
 403                         if (n < 0)
 404                                 bb_error_msg_and_die(bb_msg_invalid_arg_to, val, "status");
 405                         G.flags |= FLAG_STATUS_NONE << n;
 406                         /*continue;*/
 407                 }
 408 #endif
 409         } /* end of "for (argv[i])" */
 410
 411 //XXX:FIXME for huge ibs or obs, malloc'ing them isn't the brightest idea ever
 412         ibuf = xmalloc(ibs);
 413         obuf = ibuf;
 414 #if ENABLE_FEATURE_DD_IBS_OBS
 415         if (ibs != obs) {
 416                 G.flags |= FLAG_TWOBUFS;
 417                 obuf = xmalloc(obs);
 418         }
 419 #endif
 420
 421 #if ENABLE_FEATURE_DD_SIGNAL_HANDLING
 422         signal_SA_RESTART_empty_mask(SIGUSR1, dd_output_status);
 423 #endif
 424 #if ENABLE_FEATURE_DD_THIRD_STATUS_LINE
 425         G.begin_time_us = monotonic_us();
 426 #endif
 427
 428         if (infile) {
 429                 xmove_fd(xopen(infile, O_RDONLY), ifd);
 430         } else {
 431                 infile = bb_msg_standard_input;
 432         }
 433         if (outfile) {
 434                 int oflag = O_WRONLY | O_CREAT;
 435
 436                 if (!seek && !(G.flags & FLAG_NOTRUNC))
 437                         oflag |= O_TRUNC;
 438
 439                 xmove_fd(xopen(outfile, oflag), ofd);
 440
 441                 if (seek && !(G.flags & FLAG_NOTRUNC)) {
 442                         if (ftruncate(ofd, seek * obs) < 0) {
 443                                 struct stat st;
 444
 445                                 if (fstat(ofd, &st) < 0
 446                                  || S_ISREG(st.st_mode)
 447                                  || S_ISDIR(st.st_mode)
 448                                 ) {
 449                                         goto die_outfile;
 450                                 }
 451                         }
 452                 }
 453         } else {
 454                 outfile = bb_msg_standard_output;
 455         }
 456         if (skip) {
 457                 size_t blocksz = (G.flags & FLAG_SKIP_BYTES) ? 1 : ibs;
 458                 if (lseek(ifd, skip * blocksz, SEEK_CUR) < 0) {
 459                         do {
 460                                 ssize_t n;
 461 #if ENABLE_FEATURE_DD_IBS_OBS
 462                                 if (G.flags & FLAG_FULLBLOCK)
 463                                         n = full_read(ifd, ibuf, blocksz);
 464                                 else
 465 #endif
 466                                         n = safe_read(ifd, ibuf, blocksz);
 467                                 if (n < 0)
 468                                         goto die_infile;
 469                                 if (n == 0)
 470                                         break;
 471                         } while (--skip != 0);
 472                 }
 473         }
 474         if (seek) {
 475                 if (lseek(ofd, seek * obs, SEEK_CUR) < 0)
 476                         goto die_outfile;
 477         }
 478
 479         while (!(G.flags & FLAG_COUNT) || (G.in_full + G.in_part != count)) {
 480                 ssize_t n;
 481 #if ENABLE_FEATURE_DD_IBS_OBS
 482                 if (G.flags & FLAG_FULLBLOCK)
 483                         n = full_read(ifd, ibuf, ibs);
 484                 else
 485 #endif
 486                         n = safe_read(ifd, ibuf, ibs);
 487                 if (n == 0)
 488                         break;
 489                 if (n < 0) {
 490                         /* "Bad block" */
 491                         if (!(G.flags & FLAG_NOERROR))
 492                                 goto die_infile;
 493                         bb_simple_perror_msg(infile);
 494                         /* GNU dd with conv=noerror skips over bad blocks */
 495                         xlseek(ifd, ibs, SEEK_CUR);
 496                         /* conv=noerror,sync writes NULs,
 497                          * conv=noerror just ignores input bad blocks */
 498                         n = 0;
 499                 }
 500                 if (G.flags & FLAG_SWAB) {
 501                         uint16_t *p16;
 502                         ssize_t n2;
 503
 504                         /* Our code allows only last read to be odd-sized */
 505                         if (prev_read_size & 1)
 506                                 bb_error_msg_and_die("can't swab %lu byte buffer",
 507                                                 (unsigned long)prev_read_size);
 508                         prev_read_size = n;
 509
 510                         /* If n is odd, last byte is not swapped:
 511                          *  echo -n "qwe" | dd conv=swab
 512                          * prints "wqe".
 513                          */
 514                         p16 = (void*) ibuf;
 515                         n2 = (n >> 1);
 516                         while (--n2 >= 0) {
 517                                 *p16 = bswap_16(*p16);
 518                                 p16++;
 519                         }
 520                 }
 521                 if ((size_t)n == ibs)
 522                         G.in_full++;
 523                 else {
 524                         G.in_part++;
 525                         if (G.flags & FLAG_SYNC) {
 526                                 memset(ibuf + n, 0, ibs - n);
 527                                 n = ibs;
 528                         }
 529                 }
 530                 if (G.flags & FLAG_TWOBUFS) {
 531                         char *tmp = ibuf;
 532                         while (n) {
 533                                 size_t d = obs - oc;
 534
 535                                 if (d > (size_t)n)
 536                                         d = n;
 537                                 memcpy(obuf + oc, tmp, d);
 538                                 n -= d;
 539                                 tmp += d;
 540                                 oc += d;
 541                                 if (oc == obs) {
 542                                         if (write_and_stats(obuf, obs, obs, outfile))
 543                                                 goto out_status;
 544                                         oc = 0;
 545                                 }
 546                         }
 547                 } else {
 548                         if (write_and_stats(ibuf, n, obs, outfile))
 549                                 goto out_status;
 550                 }
 551         }
 552
 553         if (G.flags & FLAG_FSYNC) {
 554                 if (fsync(ofd) < 0)
 555                         goto die_outfile;
 556         }
 557
 558         if (ENABLE_FEATURE_DD_IBS_OBS && oc) {
 559                 if (write_and_stats(obuf, oc, obs, outfile))
 560                         goto out_status;
 561         }
 562         if (close(ifd) < 0) {
 563  die_infile:
 564                 bb_simple_perror_msg_and_die(infile);
 565         }
 566
 567         if (close(ofd) < 0) {
 568  die_outfile:
 569                 bb_simple_perror_msg_and_die(outfile);
 570         }
 571
 572         exitcode = EXIT_SUCCESS;
 573  out_status:
 574         if (!ENABLE_FEATURE_DD_STATUS || !(G.flags & FLAG_STATUS_NONE))
 575                 dd_output_status(0);
 576
 577         if (ENABLE_FEATURE_CLEAN_UP) {
 578                 free(obuf);
 579                 if (G.flags & FLAG_TWOBUFS)
 580                         free(ibuf);
 581         }
 582
 583         return exitcode;
 584 }